sched/fair: Add a few assertions

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Don Hiatt <dhiatt@digitalocean.com>
Tested-by: Hongyu Ning <hongyu.ning@linux.intel.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210422123308.015639083@infradead.org

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c209f68aad612022cc39c0fec5ea08cada9b6a36..6bdbb7bb0d66de5c6b4ebce13738de33b81df019 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6288,6 +6288,11 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
                task_util = uclamp_task_util(p);
        }
 
+       /*
+        * per-cpu select_idle_mask usage
+        */
+       lockdep_assert_irqs_disabled();
+
        if ((available_idle_cpu(target) || sched_idle_cpu(target)) &&
            asym_fits_capacity(task_util, target))
                return target;
@@ -6781,8 +6786,6 @@ unlock:
  * certain conditions an idle sibling CPU if the domain has SD_WAKE_AFFINE set.
  *
  * Returns the target CPU number.
- *
- * preempt must be disabled.
  */
 static int
 select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags)
@@ -6795,6 +6798,10 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags)
        /* SD_flags and WF_flags share the first nibble */
        int sd_flag = wake_flags & 0xF;
 
+       /*
+        * required for stable ->cpus_allowed
+        */
+       lockdep_assert_held(&p->pi_lock);
        if (wake_flags & WF_TTWU) {
                record_wakee(p);